


The Siren And The Spy

by doctorwhoper, HelldiverOfLykos



Category: Kingsman: The Secret Service (2015)
Genre: M/M, Mention of torture, Merpeople, mer!Eggsy, scientific experimentation
Language: English
Status: Completed
Published: 2016-02-19
Updated: 2016-04-26
Packaged: 2018-05-19 09:04:05
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 5
Words: 4,862
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5961745
Author URL: https://archiveofourown.org/users/doctorwhoper/pseuds/doctorwhoper, https://archiveofourown.org/users/HelldiverOfLykos/pseuds/HelldiverOfLykos
Summary: <blockquote class="userstuff">
              <p>Harry's cover gets blown while on a mission in the middle of the Pacific Ocean. But what happens when he finds the impossible... and falls in love with it?</p>
            </blockquote>





	1. Chapter 1

The first thing he registered when he opened his eyes was the overwhelming abundance of light. Blinking once, twice, the world above him slowly came into focus. There wasn't much -- a greyish ceiling with a few halogen lamps scattered here and there, evidently the source of the blinding light. One of the lights was rather inconveniently placed directly above him, making his head throb.

Harry groaned as he sat up and found that he was lying on a dirty foam mattress in a small room. There was a large glass tank that was half-filled with water sitting in the corner. The tank had a metal grille covering the top, and the top half of the glass was horribly grimy.

_Where was he?_

Oh, yes. He was on a mission in the Pacific Ocean, gathering intel on a group participating in unethical scientific experimentation. They were also involved in the trafficking of endangered animals for the production of medicines. The last he remembered, he had been on a ship to China. If the tilting of the floor underneath him told him anything, it was that he was still on the ship. 

The fuzziness in his head probably meant that he had been drugged, which in turn suggested that his cover had been blown or that somebody had caught him. Of the two, the former was the most likely. His cover had been flawless, and he had had absolutely no contact with any Kingsman personnel ever since he had boarded the ship. 

Harry rubbed his face and groaned. He looked down at himself and found that he was only wearing his shirt and a pair of jeans. His watch and shoes were gone, which meant that the only tools that he had had on him were gone as well.

_Shit. Buggering shit._

A splash from the tank of water jolted Harry out of his train of thought. Harry squinted at the glass and saw a dark blob in the slightly murky water. As the blob moved closer, Harry was surprised to see that it was a huge fish tail. He was even more surprised when a _palm_ was pressed to the inside of the dirty glass and wiped the grime away to reveal the head and torso of a young man attached to the top of the tail.

The... mermaid-- no, mer _man_ 's tail was long and slim, with deep blue and green swirled all along the length of it. The shimmering scales transitioned smoothly to the pale skin of the merman's stomach. His upper body was built like a swimmer's, the skin at the sides of his body and his neck broken by evenly-spaced gill slits. He had blonde hair and beautiful emerald-green eyes that matched the rich greens in his tail.

Harry couldn't help but gape a bit. Was he dreaming? Or hallucinating?

He stood up and staggered to the tank. The merman reached a hand through the metal grille and waved at him.

No, he definitely wasn't hallucinating.

The merman cocked his head at Harry. Harry rubbed his hands over his face again. 

"I'm in a cell with a _merman_ after getting drugged by a group of animal smugglers. Merlin is never going to believe me when I tell him," Harry chuckled.

"Who's Merlin?" a melodic voice asked.

Harry started violently, but relaxed.slightly when he realized the voice belonged to the merman.

"Merlin is a friend of mine," Harry replied cautiously.

"Oh. Does he work with them?"

"He does not belong to the organization that operates this ship, if that's what you're asking."

"Do _you_ work with them?"

"No. I was sent to gather information on their organization. Why do you ask?"

The merman simply lifted the fins at the end of his tail out of the water to show Harry. They were tattered and torn, with a few jagged holes here and there. Then, he pressed the side of his tail against the glass. Upon further inspection, Harry found that large patches of scales had been removed, and skin samples flayed from the muscle and left without medical attention. There were also a few scars scattered here and there. 

Harry realized that they had been experimenting on the poor merman. It sickened him to the core to think that any human being would hurt and _torture_ such a beautiful and (once) innocent creature.

The merman seemed embarrassed at the amount of attention Harry was giving his tail and lowered it back into the water, his face a bright red.

"How long have you been here?" Harry asked.

"A few months. I lost track after Day 76."

About 2 and a half months. The ship had been somewhere near Africa then.

"May I know your name? If you're comfortable with sharing it with me, that is."

"It's Eggsy."

"Nice to meet you, Eggsy. I'm Harry, and I'm going to find us a way out of here."


	2. Chapter 2

The merman blinked.

“And how do you think you’re going to do that?"

Harry stalked over to the door. After a moment of tussling with the brass knob, he threw himself again and again against the door, in a desperate bid to break it down, but to no avail.

He paced restlessly near the tank. If there was one thing Harry hated, it was the feeling of helplessness- the creeping realisation that there was nothing he could do about his current situation. It itched at him like a rash. Defeated, he sat down heavily on the dirty mattress.

The merman (Eggsy, he reminded himself) was looking at him impassively.

“Sometimes they come in,” he said, suddenly.

Harry looked up.

“To whom are you referring?"

“The guards,” said Eggsy, his long tail flicking back and forth through the water. “Sometimes, they come in and drag me away to this other room."

“Do you know in which direction this room might be?” asked Harry, leaning forward.

“Yeah, it’s a left and then two rights.”

“Could you describe the room for me, Eggsy?" asked Harry. If they weren’t going to get out of this cell for a while, he had might as well glean all the information he possibly could about this vessel from the merman.

Eggsy's brow furrowed in thought.

“It’s much bigger than this one, that’s for sure,” he said, after a moment of consideration. “The walls are white and there are lots of tables arranged in a corner. That’s where they conduct the experiments.” Here, the merman looked troubled. His tail flicked faster through the water, creating a mini whirlpool.

Harry felt a stab of sympathy. It was unbelievable to think that so much harm could be caused to such a gorgeous creature.

It took a while for him to realise he had been staring at the merman for longer than was strictly appropriate. He created his throat and looked away, an unfamiliar feeling rising in his stomach. There will be plenty of time for this later, he told himself sternly.

At that very moment, the door flew open. Harry immediately sprang to his feet, readying himself for combat. Out of the corner of his eye, he saw Eggsy curl into himself, trembling slightly.

Three guards stood in the doorway, each more muscular than the last. Two of them walked over to the grimy tank and hauled the still-cowering merman out. Eggsy did not resist; he allowed himself to be unceremoniously manhandled by the guards.

The third guard just stood in a far corner of the room, watching the other two work. 

Harry’s thoughts ran fast. The door was unmanned. He could risk making a run for it, returning with backup to rescue the merman and complete his mission. His window of opportunity was growing smaller by the second, though, so he needed to move immediately.

Throwing caution to the wind, Harry hurtled towards the door, blood pounding in his veins. He could hear a guard’s thundering footsteps behind him and tried to quicken his pace. He rounded corners expertly and dodged several guards trying to get a hold of him.

Just as he had thought he had lost them, he nearly ran straight into a blank grey wall. Heart hammering, he turned this way and that, looking for a way to escape. The guards would be there any second. He prodded his brain frantically.

_THINK!_

It was of no use. The burly guard whom he had met in his and Eggsy’s room spotted him from the other end of the corridor and shouted in triumph. He caught Harry by the scuff of his neck and punched him clean across the face, over and over, until he was plunged into darkness again.

***

He could hear someone calling out his name. Was it Merlin? No, that was absurd. Why would Merlin be here?

But where was here?

He sat bolt upright and regretted it immediately. Blinding pain shot through his forehead.

He sank back down onto the mattress, digging the heels of his palms into his eyes as he let out a low groan. 

As the pain became more and more bearable, the voice became less fuzzy, like a radio being tuned.

"Harry."

He answered with a groan.

“Harry, are you okay?”

Groan.

“Yeah, I’m going to take that as a no.”

He sat up much more gingerly this time. “It would be best if you do,” he said, still keeping his eyes screwed shut tightly.

"You tried to escape."

Harry slowly opened his eyes. "I did," he said, carefully, looking at the merman. Eggsy's face was bruised, one of his eyes swollen and purple. His tail was even more ragged and torn than before, and he looked exhausted.

"Why?" asked Eggsy. "You said you'd help me get out, too. You were going to run off and leave me here. You lied to me."

Harry's heart sank. He quickly walked over to the tank, crouching so that he was at eye level with Eggsy. "No, Eggsy," he said, softly. "I was not going to leave you here. I was going to find a way off this vessel and return to rescue you with reinforcements. I assure you, your thoughts could not be further from what I had planned."

Eggsy's anger and hurt seemed to dissipate, replaced by an expression of relief. "Oh."

"Yes," said Harry, frowning. "What did they do to you?"

The merman looked away. "It's nothing. I've had worse."

Guilt welled up in Harry's chest. "I'm sorry," he said, even softer than before. Eggsy locked eyes with him, and he felt a jolt of _something_ spike through his chest.

He cleared his throat.

"We need to find a way out of here," he ventured. "We need a plan. But first, I need you to tell me everything you know about the layout of this ship."


	3. Chapter 3

They spent the next few days(?) in relative peace, huddled in the tiny cell. Harry's mind raced the entire time, planning and re-planning their escape. Eggsy idly flicked water at the grimy sides of his tank.

He wanted to help Harry, he really did, but each time he asked Harry if he could help, Harry declined with a gentle "I'm fine, Eggsy."

Eggsy frowned. After he had told Harry what little he knew about the layout of the ship, Harry had retreated into his head to think.

_Fuck this shit._

Eggsy splashed a few well-aimed drops of water at Harry.

"No, Eggsy. I'm fine."

"No, you aren't. You can't do this all by yourself, Harry."

"Yes, I can. I've gotten myself out of worse situations before, Eggsy. I can get us out of this one, as well."

"Take a break, then. You haven't talked to me in ages."

"I'm talking to you right now, Eggsy."

The merman rolled his eyes.

"Smartarse. Stop thinking about the escape for just five minutes and _listen_ to me."

Harry glanced up guiltily.

"I'm sorry, Eggsy. I never meant to make you feel neglected," he said softly as he rose and walked over to Eggsy's tank.

Eggsy reached a hand through the metal grille and grasped Harry's arm.

"You have to relax a bit. That big brain of yours is no good to either of us if you think yourself to death."

Harry smiled. Eggsy smiled back, his green eyes twinkling like jewels. Harry felt a wave of fondness wash over him, but it retreated like the tide on the seashore when Eggsy suddenly drew his hand back into his tank, his face a bright red.

"You looked uncomfortable," Eggsy explained.

An unconfortable silence hung between them for a few beats.

"How much do you know about Merpeople?" Eggsy asked shyly.

"Not much, I'm afraid. I never had much interest in fairytales as a child."

"Do you want me to tell you?"

Harry smiled.

"Sure, why not?" Harry asked as he settled down next to Eggsy's tank.

"Where do you want to start?"

"How about we start with the most common myth about mermaids: the Siren Song?"

"That one's real, all right. All merpeople know the Siren's Song, but few of us actually use it to seduce unlucky sailors."

Harry raised an eyebrow at the last bit.

"Just sailors?" he smirked.

"Maybe a few girls wandering by the beach as well, but most of the ones that use the Siren's Song are mermaids that fall for sailors, and, of course, there are a few gay mermen as well..." Eggsy trailed off, shooting a cheeky wink at Harry, who rolled his eyes slightly in return.

"Is there any 'magic' involved in the Siren's Song?" Harry asked.

"Of course. I have no idea how it works, though. All I know is that there is one song that draws humans to water, and another that sort of hypnotises them into doing whatever you want them to. There's other magic out there as well, but the most common spells are those that bind lovers together, whether under the sea, on land, or in both 'realms.'"

Harry nodded.

"How about your society? What is it like?"

"It's sort of like yours, except that there are two types of merpeople: the Sirens and the Undines. The Sirens are the "normal" ones, but the Undines are hatched from eggs and their tails can transform into legs. There aren't very many of them, but they're supposed to be very beautiful, but able to kill people with just one look.

I hatched from an egg, and my ma thought I was an Undine, but it turns out that my tail doesn't turn into legs when I get out of the water. And when Dean, my stepdad came along, he didn't like me at all. Said I didn't belong in our family and that even if I really was an Undine, I was a fucking lousy one, with my tail and all."

"And that was how you got your name-- your nickname, I'm guessing?"

"Yes. My real name's Gary, but I like Eggsy. My ma used it as her pet name for me before Dean came along and twisted it into something else." Eggsy fiddled with the torn ends of his tail as he explained, stroking the filmy material gently with slim fingers.

Harry smiled sympathetically.

"You said Dean was your stepdad. If it's not too personal, may I ask what happened to your real father?" Harry asked cautiously.

"He was a soldier. He was in the last stage of his training when a hydra attacked his group. He fought it off, but not before sustaining fatal injuries. He was a hero, my dad," Eggsy murmured, staring at the glass with a faraway look in his eyes, as if he were somewhere else and not in a dirty glass tank on board an animal trafficker's ship.

"I'm sure he was, Eggsy."

"He was the one who taught me the Siren's Song, even though my ma didn't want him to. He said his dad taught it to him when he was my age," Eggsy smiled.

An idea hit Harry.

_The Siren's Song._

"Eggsy, do you still remember how to sing the Siren's Song?" he asked, his voice trembling with excitement. He _finally_ knew how they were going to escape!

"'Course. Why do yo- ohhhhhhh..." Eggsy's eyes flashed with mischief. "You're going to use it to help us get out?"

"Yes. This whole time, I've been thinking about the ways I know of to escape from situations like this, but I never bothered to factor you in. You could be the solution we need to break out!"


	4. Chapter 4

Hope lit up Eggsy's bruised face. "I can't believe we didn't think of this before," he said, chuckling

Harry started to pace back and forth. "Yes, well, now that we have, we must have a meticulous plan in place before those vultures come back"-here, Eggsy shuddered-"and try to take you away again."

Eggsy's eyes followed Harry around the room. "Harry, you need to calm down."

"Hmm? What?" Harry looked up at him, his eyes slightly wild.

"You haven't slept since you got here, apart from the time you were knocked out, and you've barely eaten anything." Eggsy motioned to the mattress. "Sit down. You're tired."

Harry seemed to deflate a little bit. He walked towards the mattress and sank down onto it.

"Okay," said Eggsy. "Now, this plan thing, what we could do is we could wait for them to come back. Once they do, I'll sing the Siren Song, which'll sort of hypnotise them, giving you time to get out, and come back with reinforcements."

"No."

"What?" Eggsy looked confused.

"I said, no." Harry gazed at Eggsy. "THere's no way I'm leaving you behind again."

Eggsy looked at him shyly. "Why not?"

Harry blinked several times, looking away. "Look, Eggsy, over the last few days that we've been in captivity together, I think I might have begun to have feelings for you that go beyond the parameters of friendship."

Eggsy's eyes widened. Harry went on. "And this really isn't the time to be discussing any sort of romantic entanglement, so maybe we should wait until we get out of here to talk about this."

"Right, fair enough," said Eggsy, biting his lip.

Harry exhaled. "Like I said, there is no way I'm leaving you behind. Once the guards have been successfully hypnotised by your song, I'll carry you out of the tank, and run out, searching for the hatch that leads to the main corridor. From there, it shouldn't be too hard to locate the exit and get out." He looked up at Eggsy. "How does that sound to you?" 

Eggsy looked slightly worried. "Harry," he began, tentatively. "There isn't any problem with the plan, except- how will we protect you from the song?" 

Harry furrowed his brow. "How do you mean?" 

"I mean, when I sing, you'll be hypnotised as well." 

Harry swore. He hadn't anticipated that. "Well," he ventured, "maybe I could just shut my ears. Isn't that what the old Greek heroes used to do? I could fashion earplugs from something, or, or, I could find some other way- I mean, obviously, there has to be some method of-" 

"Harry." Eggsy cut off his rambling. "Come here." 

"What? Why?" 

"Just come here, will you?" Eggsy floated to the top of the tank and emerged from it, rivulets of water pouring down his face as he clung to the side of the tank.

Slowly, Harry walked towards him. "What are you going to-" Eggsy caught hold of his collar and pulled him in, so that their faces were mere centimeters away from each other. "Shut up," he breathed, "and trust me." 

And he kissed him. Harry went slack, his brain blank as he struggled to comprehend what was happening. He was normally the most suave man in the room, but all that seemed to go out of the window now as Eggsy's lips moved insistently against his own. A warmth seemed to spread from his mouth to his throat, his chest, his limbs, permeating his entire body until he felt as if he could take on an entire army singlehanded. 

After what felt like several long years, Eggsy broke the kiss reluctantly, submerging back into the water. Harry blinked several times. "What," he began, then cleared his throat. "I mean, what was that for?"

Eggsy looked up at him. "You'll be immune to the song now."

"Oh." Harry seemed to have lost his entire train of thought. Struggling to find it, he said, "well." Then he slowly backed away, feeling around for the mattress and sat down. "It was... good."

Eggsy smiled, blushing slightly. "And now what?"

Harry leaned back. "And now, we wait."

***

Over the course of his illustrious career, Harry had had to wait around a lot. He waited to get into meetings. He waited for briefings on new missions. He waited for his newly tailored suits to arrive.

However, it had to be said that the next few hours were part of one of the longest and most excruciatingly painful waits of his life. Eggsy had retreated into a corner of the tank, and was humming what was possibly an approximation of the Siren Song, judging by the way Harry felt slightly drowsy.

Harry himself was sitting on the mattress with his eyes shut, visualizing ship layouts (necessary) and attack strategies (hopefully not necessary). A small part of his brain, despite himself, was thinking about what they would do once they got out of here. They'd have to swim to the shore, obviously. It could take hours and hours, though, and that was if they didn't get eaten by some larger sea animal first. But if they survived, what would they do? Harry could take Eggsy back to Kingsman. They could live together, maybe-

The door flew open.

Harry immediately stood bolt upright, and Eggsy floated to the top of the tank, poking his head out of the water.

The guard who had beaten Harry up stood at the door, flanked by another guard on either side. The middle one walked over to Harry and held on to his arms, locking them behind his back. The other two began to walk towards the tank.

Harry looked at Eggsy, who nodded grimly.

Then he opened his mouth and began to sing.

Many years later, Harry would still remember the emotions that ran through him when he heard the Siren Song for the very first time.

Eggsy's voice was rich and sweet, and it held the high notes in a manner that would put even the best of tenors to shame. Harry didn't know much about music, but he could tell that the way Eggsy sang was extraordinary. The overall effect of the song was dulled, as if he were hearing it through glass, but the way the song flowed around him still made him feel slightly afraid of exactly what Eggsy was capable of, how he could reduce people to mere puppets by just opening his mouth.

And he was doing just that. The guards' eyes had glazed over. The one restraining Harry had long since given up and was now sitting on the floor, whimpering slightly. The other two sank to their knees, staring at Eggsy's eyes were shut, frowning in concentration. He looked ethereal, brilliant, powerful.

Suddenly, it was all over. Eggsy's mouth shut and he sighed, part exhaustion, part relief. The guards were unconscious on the floor.

Harry looked at Eggsy. "You did it."

Eggsy grinned. "Let's go."

Harry ran over to the tank and hoisted Eggsy out, cold drops of water running down his arms, and hurled them out of the door. He turned left, then right, desperately looking for the exit in the veritable maze of corridors. Eggsy clung to him and soaked his shirt, occasionally whispering directions.

He darted this way and that, weaving out of the endless grey metal walls. It was a miracle they hadn't been caught by any other guards yet, Harry thought.

Just then, he heard a shout. He looked at Eggsy.

"Run!" Eggsy yelled, shoving at him.

He ran in the opposite direction of the voice, frantically looking for the hatch. Turning, he saw a staircase that would lead them up to the forecastle area. Or at least that's what he hoped.

Holding on to Eggsy, he raced up the flight of stairs. The voice had become clearer now. They were definitely on his tail.

He burst through a door and breathed in fresh air. Wincing, he forced his eyes to stay open even through the sudden onslaught of sunlight.

A vast expanse of sea unfolded before them, dappled with white foam here and there. From somewhere, a horn sounded.

Behind them, a guard called out. "They're here!"

Harry locked eyes with Eggsy, and saw only determination and trust there.

Taking a deep breath, he ran to the bow of the ship and threw himself and Eggsy over it. He cradled Eggsy in his arms, closing his eyes and waiting for the impact of the icy cold seawater.


	5. Chapter 5

**Notes for the Chapter:**

> I'M SO SORRY THIS TOOK SO FUCKIN LONG IN COMING BUT I HAD THIS MASSIVE WRITER'S BLOCK AHGDSKASDHFA
> 
> I really hope this makes up for such a long wait... Thanks for reading!
> 
> ~Helldiver

_Five months later_

"Have you quite finished, Eggsy?" Harry called through the bathroom door. "It's been almost half an hour. Are you all right?"

Splashing sounds bled through the door, along with a _slap_.

"I'm fine, Harry. Just give me a minute."

"You used the bathtub again, didn't you?"

A beat of silence passed.

"Maybe?" came the sheepish reply.

Harry groaned.

"How many times must I tell you not to use the bathtub? You know you always get stuck."

"Well, forgive me for stretching my fins, my dear Mr. Hart."

"I'm coming in," Harry said as he pushed the door open, revealing one very embarrassed Eggsy sitting in the bathtub, shimmering fins spilling over the edges of the tub. Half the floor was covered in water, and Harry had to watch his footing as he approached the blushing merman.

A few months ago, after jumping off the smugglers' ship, Harry had awoken to the sight of a boy with emerald eyes bending over him. A boy, not a merman, for when Harry had glanced further down, there had been legs (and a fair-sized... _ahem..._ something between them) instead of shiny scales. "Guess I was a late bloomer," he had shrugged, before grabbing Harry's face and kissing him thoroughly. After they had reestablished contact with Kingsman, Merlin had posted them at a location on the beach of a tiny bay on the West Coast of the U.S. Eggsy was grateful for the warmer waters and the bright sunlight as opposed to the colder currents around the British Isles. Harry had begun training Eggsy to be the first Merperson to ever become a Kingsman. Merlin had agreed, as he was sure Eggsy had the potential to become a valuable asset both in and out of the water.

"You never do learn from your mistakes, do you? Your tail and fins always decide to make their appearance when you're submerged in water. Do you need a reminder of what happened the last time I took you out in the boat?"

Eggsy smirked to himself, his bright blue eyes flashing with mischief. They had once taken a yacht (decked out with Kingsman equipment, weapons, and a very well-stocked bar, if Harry did say so himself) out in the small bay that they were now living on the beaches of. Harry had taken the opportunity to catch up on some sleep in a deck chair in the sunlight, while Eggsy had slipped off to exercise his tail muscles after about a month of living out of the water. Unfortunately, he had gone too close to the shore (and about 10 other boats _WITH PEOPLE ON THEM_ ) and soon after, there were photographs of _**ACTUAL MERMAID SPOTTED**_ or _**OMG YOU WONT BELIEVE YOUR EYES LOOK ITS A FUCKING MERMAID**_ flying around the internet.

Harry and Eggsy had completely different reactions to the Undine's sudden internet fame.

"WHAT THE FUCK IS THIS, EGGSY?" Harry had thundered, his face bright red, as he had dragged Eggsy to see a photo of a blur of sparkling blue scales, lightly tanned skin, and light brown hair streaking through the clear water of the West Coast.

Eggsy's jaw had dropped as he stared at the post on Twitter. According to Merlin, who had been tracking the post, it had gone viral within 2 days, along with other posts with similar photos of what appeared to be a merman with a blue tail.

"Why the fuck do they think I'm a MERMAID???" Eggsy had exclaimed, earning himself a glare from Harry and a lecture on not going swimming anywhere near the coast, other boats and ANY OTHER PEOPLE EXCEPT HARRY.

"Are you trying to remind me of that incident itself, or the lecture you gave me?" Eggsy grinned cheekily from inside the bathtub.

"I'm trying to remind you of what happens when you piss me off, Eggsy," Harry said sternly.

"Yeah, you yell at me, I say sorry, you forgive me and tell me not to do it again, and we have mind-blowing make-up sex after."

Harry rolled his eyes, pushing up his sleeves.

"Let's get you out of that tub."

"It's gonna end like it usually does, right?"

"Of course, Eggsy."

**Notes for the Chapter:**

> Thanks for reading! We really hope you enjoyed it :)
> 
> I'm willasherlyscottholmes and doctorwhoper is boffinholmes on tumblr!


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